Pawn-45 Early Fight.

Static rook, a rapid attack on a ranging rook · castles into Boat · ４五歩早仕掛け yon-go fu hayashikake

The idea

The Pawn-45 Early Fight is the other answer to White’s silver on 4c. From the Left Silver-57 position, where the Left Silver-46 takes the silver on to 4f, Black pushes the fourth-file pawn instead, to 4f and then 4e, and brings the knight up to 3g. Then the strikes come one after another: the pawn to 2d, the pawn to 4d, and a pawn dropped back on 4e.

The bishops come off, Black’s knight is traded for White’s silver, and the line ends with Black’s rook on 2d. ja.wikipedia, after Watanabe Akira’s book on beating the Fourth File Rook, explains why it works here: White needs two moves to make the Mino safe, the 7d pawn and the gold to 6c, and in this line White has played only the gold, so the Mino is open to a knight dropped on 8f or 7e.

It rates the end better for Black.

How it goes together

Both sides’ moves are shown, because this opening is an agreement rather than a system: one player cannot reach it alone, so a one-sided list of moves would be a fiction.

The plan once you are set up

• Build the Boat and the Left Silver-57 position.
• When White’s silver comes to 4c, push the fourth-file pawn to 4f and 4e instead of moving the silver.
• Bring the knight to 3g, then strike: 2d, 4d, and a pawn dropped on 4e.
• Trade bishops and take on 2d with the rook.

What to watch for

• White’s king’s-head silver: the silver to 5d instead of the pawn, heading for 6e and 7f. It is White’s strong answer to this plan.
• White’s second move for the Mino. With both the 7d pawn and the gold on 6c in, the Mino holds and the attack does not work.
• It needs a Fourth File Rook: ja.wikipedia says it does not work against a Third File Rook played as Black.

What it is played against

A Fourth File Rook with a Mino and the silver on 4c, where White has played only one of the 7d pawn and the gold to 6c. White’s strong answer is the king’s-head silver on 5d.